The definition of a neutron is a nucleon with no charge.
An example of a neutron is something that turns into a proton and electron.
Particle Physics an uncharged nucleon having a mass of c. 1.675×10 kg (c. 939.5729 MeV/c, c. 1,839 times the mass of an electron): a free neutron, as in nuclear fission, has a half-life of c. 14.8 minutes, is readily absorbed by a nucleus, and decays into a proton, an electron, and a neutrino
Origin of neutronneutr(al) + -on
The electrically neutral nucleon, a baryon composed of two down quarks and one up quark, which has a mass 1,839 times that of an electron, is stable when bound in an atomic nucleus, but has a mean lifetime of 886 seconds as a free particle. It is a basic component of all atomic nuclei except the protium isotope of hydrogen.
Origin of neutronneutr(al) + –on1.